1. Field of the Invention
This invention relates to infrared thermopile systems for semiconductor process monitoring and control, and to a method of monitoring and controlling semiconductor processes using infrared thermopile sensing of conditions in and/or affecting such processes.
2. Description of the Related Art
Sensors and monitoring devices used in the semiconductor industry generally have two purposes. One type of such device is used as a safety sensor to warn persons (e.g., personnel operating the semiconductor process equipment or otherwise in proximity to such equipment) of the presence of toxic or otherwise hazardous materials associated with the process in the ambient environment of the process system. These safety sensors, sometimes termed “life safety sensors,” have lower detection limits consistent with the threshold limit values (TLVs) of the gases and vapors to be detected. By way of example, an arsine gas safety sensor may have a lower detection limit of 50 parts per billion by volume (ppbv), so that any concentration of arsine that is 50 ppbv or higher will be sensed by the safety sensor device.
The other purpose for which sensors and monitoring devices have been used in the semiconductor industry is controlling semiconductor process. Examples include SiF4 ultraviolet (UV) emission detectors that are used to provide a signal indicative of the completion of chamber cleaning operations.
The semiconductor manufacturing field continues to seek improvements in process monitoring and control.